Gels are generally formed when attractions between molecules facilitate the formation of an extensive three-dimensional network that traps the solvent between "strands" of the network. For example, organic gel-forming materials may have multiple polar functionalities that allow for network formation by hydrogen bonding.
Agents able to immobilize organic solvents as gels have many potential applications. For example, these materials could be used to gel marine oil and chemical spills and assist in their containment and recovery, particularly with a water insoluble gelling agent. Additionally, there may be applications in chemical synthesis because reactions occurring in a gelled solvent may proceed at different rates or with different regio- or stereo-selectivity as compared to similar reactions in traditional solvents. These materials might also be employed in the development of new chromatographic stationary phases or semi-permeable membranes, in the transfer of organic liquids, or in the application of solvents, like methylene chloride, in a gelled state (U.S. Pat. No. 4,986,936; U.S. Pat. No. 4,479,825). For example, it would be advantageous to gel organic liquids, such as fuels, industrial solvents and organic additives, prior to transportation, either for further use or disposal, in a gelled state. This gelled state would be more stable, less volatile, and easier and safer to contain in the event of an accident en route. One may even speculate as to the stabilization of organic liquids under near-zero gravity conditions of vehicles in earth orbit.
Alternatively, it would be beneficial to develop components for use in thixotropic materials. For example, compounds that gel organic liquids, such as acetone, toluene, benzene, ethyl acetate, alcohols, and methylene chloride, would be useful in varnish and paint remover to facilitate its storage, transportation and application. Wood stains are often benefitted by a gel formulation and could be prepared using the methods, compositions and compounds of the present invention. The formulation and/or stabilization of organic emulsions should also be aided by the new gel compositions of the present invention.
Unfortunately, compounds which cause gellation of organic solvents are unused and often complex and expensive to prepare. For example, Kobayashi describes the use of various compounds, including sorbitol derivatives, as gelling agents. (JP 05,320,617, JP 04,368,389, JP 04,352,787, and JP 03,281,684). JP 53,124,595 describes the gellation of an organic liquid by the incorporation of a gel of an alicyclic alcohol, which contains the alicyclic alcohol and the condensation product of an aromatic aldehyde and a polyhydric alcohol.
The present invention alleviates many of the problems inherent in the prior art by providing water insoluble organic gelling agents that are relatively simple and inexpensive to prepare.